Vulnerability-Lookup

FKIE_CVE-2026-40477

Vulnerability from fkie_nvd - Published: 2026-04-17 22:16 - Updated: 2026-08-04 13:18

Severity

9.0 (Critical) - CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H
8.5 (High) - CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H

Summary

Thymeleaf is a server-side Java template engine for web and standalone environments. Versions 3.1.3.RELEASE and prior contain a security bypass vulnerability in the expression execution mechanisms. Although the library provides mechanisms to prevent expression injection, it fails to properly restrict the scope of accessible objects, allowing specific potentially sensitive objects to be reached from within a template. If an application developer passes unvalidated user input directly to the template engine, an unauthenticated remote attacker can bypass the library's protections to achieve Server-Side Template Injection (SSTI). This issue has ben fixed in version 3.1.4.RELEASE.

References

URL	Tags
security-advisories@github.com	https://github.com/thymeleaf/thymeleaf/security/advisories/GHSA-r4v4-5mwr-2fwr	Vendor Advisory
0b0ca135-0b70-47e7-9f44-1890c2a1c46c	https://access.redhat.com/errata/RHSA-2026:21772
0b0ca135-0b70-47e7-9f44-1890c2a1c46c	https://access.redhat.com/security/cve/CVE-2026-40477
0b0ca135-0b70-47e7-9f44-1890c2a1c46c	https://bugzilla.redhat.com/show_bug.cgi?id=2459344
0b0ca135-0b70-47e7-9f44-1890c2a1c46c	https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-40477.json

Impacted products

	Vendor	Product	Version
	thymeleaf	thymeleaf	*

JSON

To clipboard

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          "vendor": "thymeleaf",
          "versions": [
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          ],
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          "packageName": "spring-boot-starter-thymeleaf",
          "product": "Red Hat Single Sign-On 7",
          "vendor": "Red Hat"
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  "lastModified": "2026-08-04T13:18:33.790",
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CVE-2026-40477 (GCVE-0-2026-40477)

Vulnerability from cvelistv5 – Published: 2026-04-17 21:53 – Updated: 2026-08-17 12:04

Title

Improper restriction of the scope of accessible objects in Thymeleaf expressions

Summary

Severity

9.1 (Critical)


                        
                          CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H

8.5 (High)


                        
                          CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H

SSVC

Exploitation: none Automatable: no Technical Impact: total

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-04-21 00:00 UTC

CWE

CWE-917 - Improper Neutralization of Special Elements used in an Expression Language Statement ('Expression Language Injection')
CWE-1336 - Improper Neutralization of Special Elements Used in a Template Engine

Assigner

GitHub_M CNA under the mitre root

CNA scorecard C 72/100 over 7760 records in the last 180 days details

References

5 references

URL	Tags
https://github.com/thymeleaf/thymeleaf/security/a…	x_refsource_CONFIRM
https://access.redhat.com/security/cve/CVE-2026-40477	vdb-entryx_refsource_REDHAT
https://bugzilla.redhat.com/show_bug.cgi?id=2459344	issue-trackingx_refsource_REDHAT
https://security.access.redhat.com/data/csaf/v2/v…	x_sadp-csaf-vex
https://access.redhat.com/errata/RHSA-2026:21772	vendor-advisoryx_refsource_REDHAT

Impacted products

11 products

Vendor	Product	Version
thymeleaf	thymeleaf	Affected: < 3.1.4.RELEASE
thymeleaf	org.thymeleaf:thymeleaf-spring5	Affected: < 3.1.4.RELEASE
thymeleaf	org.thymeleaf:thymeleaf-spring6	Affected: < 3.1.4.RELEASE
Red Hat	Red Hat OpenShift Dev Spaces 3.28	Unaffected: 1779528224 , < * (rpm) cpe:/a:redhat:openshift_devspaces:3.28::el9
Red Hat	Red Hat OpenShift Dev Spaces 3.28	Unaffected: 1779359423 , < * (rpm) cpe:/a:redhat:openshift_devspaces:3.28::el9
Red Hat	Red Hat build of Apache Camel for Spring Boot 4	cpe:/a:redhat:camel_spring_boot:4
Red Hat	Red Hat Fuse 7	cpe:/a:redhat:jboss_fuse:7
Red Hat	Red Hat JBoss Enterprise Application Platform 7	cpe:/a:redhat:jboss_enterprise_application_platform:7
Red Hat	Red Hat JBoss Enterprise Application Platform 8	cpe:/a:redhat:jboss_enterprise_application_platform:8
Red Hat	Red Hat JBoss Enterprise Application Platform Expansion Pack	cpe:/a:redhat:jbosseapxp
Red Hat	Red Hat Single Sign-On 7	cpe:/a:redhat:red_hat_single_sign_on:7

Show details on NVD website

JSON

To clipboard

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Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Vulnerability timeline

Sightings and recorded dates, grouped by day · UTC

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The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.

Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.

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